1. Technical Field
The present disclosure relates generally to digital imaging as well as material cutting machines for handicrafts, and more particularly, to the correction of acquired images from which designs for cutting patterns are created.
2. Related Art
Handicraft encompasses the design and creation of a wide variety of decorative and utilitarian articles utilizing a range of different media, including paper, textiles, leather, wood, metal, glass, stone clay, and so forth. With the widespread availability of detailed project instructions and information on useful techniques in print and especially online, and fueled by the popularity of the individualist, do-it-yourself ethos, interest in and pursuit of the crafts has been increasing. In many instances, the article sought may simply not be available on the market, too costly to purchase, or too low of a quality. Alternatively, the personal satisfaction and empowerment experienced as result of engaging in the creative process may be the primary motivation. Regardless of the reasons, hobbyists are finding value and enjoyment in handicrafts. Some of the more skilled have found a receptive market for the articles, and with the aid of specialty handicraft oriented e-commerce services, have turned what was otherwise a leisure time activity into secondary sources of income, and even full-time occupations.
Although many projects require specialized tools as well as extensive training and education over a long period of time, some of the more accessible are those that involve working with sheet materials and creating designs therefrom. Indeed, cutting paper, textiles, and other like materials into different patterns is oftentimes part of primary school and adolescent education. More sophisticated forms of handicraft with sheet material (in whatever form) find application in scrapbooking, card making, home decorating, and so forth. For example, different shapes, titles, and paper embellishments can be added to scrapbook pages, as well as greeting cards. Various graphical designs may be first printed onto the paper sheets, and then cut for application on to another article or surface. Along these lines, labels and other designs cut from vinyl sheets can be affixed to wall surfaces and articles in the home to enhance their appearance. Such vinyl labels can also be attached to glass surfaces with the exposed portions being etched in the reverse of the label design. However, because manually cutting complex designs with scissors, hobby knives, and other hand tools can be a difficult and cumbersome process, particularly where the same design is being reproduced and/or when the precision is required, several automation devices have been developed for the handicraft market.
One such device is the cutting machine, which is generally comprised of a cutting tool that is positioned and driven by an electronically controlled motor, with the specific signals to the motor for the positioning and cutting operations being provided by an on-board controller. Cutting patterns are defined by a set of positioning and cutting instructions with parameter values therefor to the controller, whereupon execution, the tool is operated in accordance with those instructions. The sheet material, in whatever form, is affixed to a cutting mat that has peripheral registration marks that help align the work piece. Along these lines, the cutting patterns also include work piece feeding parameters, as the tool heads are typically operable along a single axis. With a basic cutting machine, all of the aforementioned sheet material projects could be made with ease, and minimizing the importance of manual dexterity in achieving excellent results. Generally, if a handicraft project calls for any cutting of sheet material, a cutting machine can perform the task with greater precision and speed.
Because earlier products targeted a user base that may not necessarily have had experience with personal computers, such cutting machines were designed as standalone devices with minimal operating complexity. Thus, only a limited number of predefined cutting patterns stored on an on-board memory module were available for selection. Some devices employed interchangeable memory cartridges that expanded the options of cutting patterns available. The user interface for making the desired selections tended to be minimalistic, as they were integrated with the cutting machine.
As the prevalence of personal computers and the comfort level of the target user base with its operation have increased, the control and pattern selection functions. i.e., the user interface functions, for cutting machines gradually shifted thereto. With most computer users being familiar with the setup and operation of printers, the similarities of cutting machines in that regard eased the adoption of these improved devices. Like a conventional printer, the on-board controller of the cutting machine communicates bi-directionally with the personal computer via Universal Serial Bus (USB) or other like short range wired or wireless data communications modality. The computer, in turn, includes driver software for interfacing directly with the controller, as well as application software through which the user can select cutting patterns. Again, these patterns represent instructions to the controller to move and operate the tool in accordance with specific parameters, also referred to as cut paths, and are defined in terms of vectors extending between a starting point and an ending point along coordinate axes.
Some cutting machine and operating software combinations have retained the aforementioned conceptual model of grouping a limited number of pre-made patterns into a single “cartridge” or module for the sake of continuity and maintaining ease of use. Rather than switching physical modules connectible to the cutting machines, collections of patterns could be downloaded online and installed on the personal computer. In addition to the downloadable patterns, the software could include default sets that were provided at the time of installation. Via the graphical user interface, selections of desired cutting patterns from the catalogue of available ones could be made and executed on the cutting machine.
Although pre-designed patterns fulfilled many needs, advanced users desired true customization in which the cutting patterns could be individually designed. Oftentimes it is desirable to start with an existing image or design graphic such as drawings, paintings, photographs, and other artwork, and create a pattern therefrom. In many cases, the artwork was created manually and does not exist in a digital form that can be manipulated with the personal computer, and there would be no cutting patterns either. However, even where there is a digital version of that artwork, the cutting patterns therefor usually do not exist. As indicated above, cut paths are defined in terms vectors between a starting point and an ending point, and so it would be necessary for users to draw each these cut path vectors via the graphical user interface. The process of defining the cut paths can be automated to some extent, but accurate reproduction of the artwork and creation of the cutting pattern depends on a quality underlying image.
This concern is particularly acute with acquired images. Cameras on mobile devices, as well as digital cameras in general are widely available and utilized for a variety of image capturing tasks. Additionally, high resolution desktop scanners are becoming more accessible to hobbyists from both the technology and cost standpoint. However, despite significant technical improvements, the problem of image quality remains.
With respect to camera capture, it is impractical for the user to take photographs of the artwork that is exactly a front/orthogonal view, as some distortion in perspective and rotation is almost inevitable. Once an image including such distortions is captured, it is possible to correct the same by identifying corner markings that serve as a reference, and altering the remainder of the image to reverse the error. Earlier techniques for identifying the corner markings involved the manual input/designation thereof, but this added step may be bothersome to the user, and is another opportunity to introduce human error. Accordingly, a more automated process is needed.
As a matter of principle, as few as four corner marks should be sufficient to deduce the necessary transformations to eliminate the perspective error. However, interference from other visual components that may have been inadvertently captured along with the desired artwork, such as nearby desktop clutter, produces unreliable and unsatisfactory results. Poor lighting conditions, extreme shadows, and noise further compounds the difficulty of correctly identifying error correction reference points.
Proper acquisition of artwork via a scanner also has associated challenges, though not necessarily the same ones as with a camera. The article can be placed consistently and accurately perpendicular to the optical plane of the scanner imaging element, thereby minimizing perspective errors. The scanner bed may be smaller in size than the artwork, so it may be necessary to scan different parts of the image in separate scanning passes, and then stitch those separate images together automatically with the correct alignment. Furthermore, the user cannot be expected to manually place the artwork into the scanner in exact alignment with the coordinate systems of the cutting machine and the software application.
Accordingly, there is a need in the art for the correction of acquired images from which designs for cutting patterns are created to eliminate perspective and rotation errors. There is also a need in the art for properly identifying features within the acquired images that are indicative of perspective, rotation, and positioning errors despite the existence of extraneous objects and noise, whether acquired via camera or via scanner.